High-quality computed tomography (CT) colonoscopy diagnostic images can be maintained while reducing the radiation dose, according to a new study. This is important because colorectal cancer screenings are more widely using CT colonography, or virtual colonoscopy.

Decreasing the tube voltage was found not to negatively impact the integrity of the CT colonography.

“Radiation dose is a concern for many in health care—from the clinicians and patients to the government agencies that regulate the industry,” said Kevin J. Chang, MD, of Rhode Island Hospital and lead author of the study. “The theoretical risks of radiation exposure as a cancer-causing agent must be weighed realistically against the substantial benefits of colon cancer screening.”

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According to the American Cancer Society (ACS), colorectal cancer is the third most common cancer diagnosed in both men and women in the U.S. The ACS estimates that in 2013, the United States will see 102,480 new cases of colon cancer, and 40,340 new cases of rectal cancer. Colorectal cancers are expected to cause about 50,830 deaths during 2013.

The study was conducted to assess the effect of decreasing the radiography voltage on dose and ultimately on 3D image quality in patients undergoing CT colonography, and how these changes are affected by patient size. After studying the CT colonography results in 63 patients, the results showed a statistically significant decrease in radiation dose while only slightly decreasing 3D image quality in patients of all sizes. The findings were published in Radiology (2013; doi:10.1148/radiol.12120134).

Chang says that more study is needed, but that he and other experts anticipate even more decreases in CT radiation dose in the coming years.

“Colorectal cancer screenings are an important part of preventative medicine,” Chang said, “and by lowering the radiation dose, we can lower patients’ concerns and their exposure, while maintaining the diagnostic quality of the exam and providing early detection and treatment.”